Radiant heating panel



May 22, 1962 D. A. AITKEN ET AL RADIANT HEATING PANEL 3 Sheets-Sheet 1 Filed Nov. 9, 1960 was INVEN kwN May 22, 1962 D. A. AITKEN ET AL 3,036,191

RADIANT HEATING PANEL Filed Nov. 9, 1960 5 Sheets-Sheet 2 INVENIORS a as/M,

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RADIANT HEATING PANEL Filed Nov. 9, 1960 3 Sheets-Sheet 3 IN VEN TORS CJWAM- D United States This invention relates to radiant heating panels and more particularly to electrically energized radiant heating panels adapted for heavy industrial uses under adverse conditions.

In industrial facilities which require the use of coal or which are involved in the handling of ore or other aggregate material, the problem of thawing large carloads of this material during the winter months is very acute. The use of fuel burners to thaw the contents of railroad cars is a past practice which is both undesirable from the standpoint of expense and dangerous in that it gives rise to detrimental effects on the cars and other equipment.

The most recent development in this field provides a plurality of infra-red heating panels arranged in three banks, one on either side of a railroad track and one located between the rails such as to be situated beneath a railroad car, the contents of which is to be thawed. The entire cluster of panels and the section of track are usually housed in a shed or the like so that some heat retention is provided in the immediate area occupied by the car.

While the use of electric infra-red or radiant heating panels is inexpensive in theory and highly eificient as to rate of heat transfer, a serious problem has arisen with respect to maintenance of the heating panels located beneath the railroad car. When the contents of the car begin to thaw, the moisture frozen therein drains into the heating panels along with fines and other foreign matter which collect around the heater elements and cause burnouts. Even quantities of material not suficient to smother the heating elements will discolor and encrust the reflecting surfaces greatly reducing reflectivity and resulting in radiant heat loss.

In addition, the individual heating elements operating at sheath temperatures of 1550 to 1650 degrees Fahrenheit under normal exterior operating temperatures of to degrees Fahrenheit present problems of unequal component expansion and contraction which creates buckling and distortion of the heating panels.

It is therefore a primary object of this invention to provide a radiant heating panel structuresuitable for use beneath railroad cars and the like which is not adversely affected by moisture and dirt falling therein.

Another object of this invention is to provide a radiant heating panel having a novel reflector structure for preventing liquid, dirt and other matter from collecting around the. heating elements therein.

Still another object of this invention is to provide a radiant heating panel structure which is not adversely affected as to expansion and buckling brought about by high operating temperatures and temperature gradients.

These and other objects of this invention will become apparent with reference to the following specification and drawings which disclose a preferred embodiment of the invention.

In the drawings:

' aten t ice FIGURE 1 is a top plan view of the invention; FIGURE 2 is a side elevation of the invention; FIGURE 3 is an end View of the invention;

FIGURE 4 is a detail taken in cross-section along line 4-4 of FIGURE 1;

FIGURE 4a is a detail of FIGURE 4;

FIGURE 5 is a detail taken along line 55 of FIG URE 1;

FIGURE 6 is a detail in partial elevation of a dotted line portion of FIGURE 3;

FIGURE 7 is a cross-section taken along line 7-7 of FIGURE 1; and

FIGURE 8 is a schematic representation of a crosssection taken along line 8-8 of FIGURE 1.

Referring in detail to the drawings and more particularly to FIGURES 1, 2 and 3, the radiant heating panel is shown as comprising a generally rectangular frame comprising a pair of longitudinal channel members 10 alrid 12 and a pair of end plates 14 and 16 of aluminum a oy.

The top of the frame is open to expose a plurality of U-shaped rods 18 or the like which comprise the electric heating elements of the device. Immediately below the heating elements 18 is positioned an aluminum alloy reflector 20 which is integrally attached at one end to the end plate 16 by welding or other suitable means. The other end of the reflector 20 is integrally connected by welding or the like at 22 to the back wall 24 of a header box 26 which is housed in the end of the rectangular frame defined by longitudinal members 141 and 12 and end plate 14. The longitudinal channel members 11) and 12 are also welded to the ends of the header box 26 along junctions 27 as shown in FIGURE 1.

The reflector 20' is shown in FIGURES l, 2 and 3 as generally comprising a pair of sloping side sections joined at the center of the reflector in a peak 28. Sloping down away from the peak 28, the side sections of the reflector extend down and out beyond the confines of the rectangular frame and terminate in a pair of integral troughs 30 and 32 parallel respectively to the longitudinal frame members 10 and 12.

The heating elements 18 extend from their free ends at the rear wall 24 of the header box 26 parallel to the longitudinal frame members 10 and 12 to a point adjacent the end plate 16 where they make a U-bend and return back to the header box 26. A plurality of lateral supports 34 are suspended from integral brackets on the inner Walls of the longitudinal frame members 10 and 12 above the peak line 28 of the reflector 20 for the purpose of securing the heating elements 18.

Referring to FIGURES 4 and 4a, for the heating elements 18 is shown one end thereof a U-shaped bracket 36 integral with the inner Wall of the longitudinal frame member 10. The actual heating element support comprises a stainless steel section 40, bolted through the side channels 10 and 12 by bolts 41, having a turned lower edge 42 seated in the U-shaped bracket 36. Slots 44, such as shown in the partial detail of FIGURE 40, are cut in the upper edge of the steel section 40 for the purpose of receiving the heating element 218 as shown in FIGURE 4. The heating elements 18 may be locked in place by an inverted U- shaped cap 46 which fits over the upper edge 48 of the steel section 40 and is held in place thereon by bolts or pins 50.

lateral support 34 as comprising on As shown in FIGURES l and 5, the longitudinal frame members or channels and 12 are joined with the end plate 16 of the rectangular frame by means of internal end gussets 52. The gussets 52 are integrally affixed to the end plate 16 but are fastened to the longitudinal channels 10 and 12 by means of bolts 54 or the like. The bolts extend through parallel longitudinal slots 56 in the leg 58 of the gusset 52 which is in juxtaposition with the inner walls of the channels 10 and 12.

As shown in FIGURES 3 and 6, the reflector 2G is reinforced at the peak 28 thereof by means of a V-shaped steel stringer 60 having a peak 62 disposed opposite to the peak 28. A pair of flanges 64 and 66 extend from the V-shaped stringer 60 to provide means by which a plurality of retaining bolts 68 may be utilized to hold the supporting stringer 60 securely beneath the peak 28 of the reflector 20. Oversize holes 70 are drilled both in the flanges 64 and 66 and through the surface of the reflector 20 whereby ample bolt play is permitted for the purpose of side and end expansion.

The details of the header box 26 are shown in FIG- URES l, 2, 7 and 8.

In FIGURE 7, the cross-section shown includes a plurality of bus bars 72, 74 and 76 for the introduction of three phase power to the heating elements. Other types of power sources may be provided in other embodiments such as single phase alternating or direct current. The free ends of the heating elements 18 are mounted in the rear wall 24 of the header box 26 by means of threaded lnconel metal terminals '78 combined with a waterproofing gasket 80 and nut 82 for securing same to the wall 24. An exemplary connection $4 is shown between the terminal 78 and the bus bar 76.

The relative position of the bus bars 72, 74 and 76 and the free ends of the heating elements 18 is schematically indicated in FIGURE 8. The bus bars are shown as mounted in slotted dielectric spacers 86. End wall insulators 88 of the same or similar material as the spacers 86 are also provided to fully insulate the interior of the header box 26. A port 90 is provided in one end wall of the header box 26 to permit a three-phase lead to be brought into the header box 26 for connection with the bus bars 72, 74 and 76.

The header box 26 is shown in FIGURE 7 as having a waterproof cover comprising the end plate :14 of the rectangular frame bolted securely to the open end of the header box 26 by bolts 92 acting to compress therebetween a resilient sealing gasket 94.

Having described in detail the structure of the radiant heating panel comprising this invention, the particular operational adaptability of the panel to environmental conditions will now be more fully set forth.

The invert-V or peaked shape of the aluminum reflector 2t and the integral trough members 30 and 32 extending along the lower extremities thereof provide a means by which spillage and fines from railroad cars overhead may be properly drained away from the heat ing elements '18 whereby burnout of the heating elements is prevented. The trough members 30 and 32 also serve to intercept radiation which might otherwise overheat and perhaps ignite adjacent materials such as wooden railroad ties.

In addition, the waterproof construction facilitated by the gaskets 94 and 80 in the header box permit the entire assembly to be hosed down while in operation to further drain away fines and spillage by way of the novel reflector and trough structure 20, 30* and 32. This hosing-down is an essential part of the thawing operation and therefore a heating panel which cannot survive this maintenance procedure cannot successfully serve as an undercar unit. 7

Because of the high temperature gradients to which the apparatus is subjected an extreme amount of expansion and contraction of components at varying or uneven rates is experienced throughout the heating panel.

Here, the novel effects of the combined use of steel for strength and slotted and free mounted couplings and supports makes possible the primary use of aluminum alloy to reduce weight and enhance corrosion resistance.

The steel reinforcing bracket 60 beneath the peak 28 of the aluminum reflector 20, the stainless steel heating element support sections 34, and the steel end gussets 52 provide a rigidity of structure that effectively resist forces set up by non-uniform expansion rates to prevent buckling of the radiant panel structure.

The non-uniform temperature coefiicients of expansion between the steel and aluminum structural components are compensated as follows:

The variance in lateral and longitudinal expansion between the steel support stringer 60 and the aluminum reflector 211 is provided for by the oversized bolt holes 70 in the flanges 64 and 66 of the stringer and in the surface of the reflector 20 adjacent the peak 28;

The variance in expansion between the stainless steel heating element supports 34 and the lateral movement of the longitudinal channels 10 and 12 occasioned by the expansion of the end plates 14 and 16 and header box 26 laterally of the entire unit is compensated by the free seating of the turned lower edge 42 of the steel supports 34 in the integral U-shaped brackets 36 on the inner walls of the longitudinal channels 10 and 12;

The variance in longitudinal expansion of the reflector 20 and the longitudinal channels 10 and 12 is compensated by the slotted'connections 56 in the arms 58 of the end gussets 52 between the channels 10 and 12 and the end plate 16.

The heating elements are also free to independently expand and contract by means of the free mounting afforded by the slots 44 in the steel support members 34.

It is to be understood that the term peak as used herein and the V-shape of the supporting means for the peak is only descriptive of the preferred embodiment shown. The peak is to be interpreted as any portion of the reflector 20' which is higher than any other portion thereof; and domed or cylindrical cross-sectional forms of the reflector 20 can be used as well as the specific peaked cross-section illustrated above. The supporting means then is no longer necessarily V-shaped but can be shaped to complement the particular cross-section used,

As can be seen from the foregoing description this invention provides a durable, trouble free radiant heating panel for use under the most harsh adverse conditions by a combination of novel structural interconnections which achieve an optimum in operational stability.

It is to be understood that the embodiment shown and described herein is for the purpose of example only and is not intended to limit the scope of the appended claims.

We claim:

1. A radiant electric heating panel comprising a substantially rectangular frame including an aluminum alloy header box at one end thereof and an aluminum alloy end plate at the other interconnected at respective ends thereof by a pair of longitudinal aluminum alloy channel members integral with said header box and slidably interconnected with said end plate; said frame havinga pair of open sides; an aluminum alloy reflector closing one of the open sides of said frame integrally connected with said header box and said end plate and having a steel reinforcing member slidably interconnected therewith extending longitudinally thereof from a point immediately adjacent said header box to a point immediately adjacent said end plate, a plurality of U-shaped heating elements extending at the open ends thereof from said header box parallel to said channel members to the U-bends therein adjacent the said end plate; a plurality of parallel lateral supporting means for said heating elements extending across said frame member from one channel to the other, each of said supporting means comprising a pair of U-shaped supporting brackets integrally and oppositely mounted one on each of said channel members on a surface thereof interior of said frame, and elongated steel sections extending between said brackets and being freely retained thereln;

whereby the combination of said steel reinforcing and heating element supporting means with said aluminum 'alloy frame and reflector provide a lightweight unit with high rigidity to resist buckling and twisting and said shdable connections between the steel members and the aluminum alloy members provide automatic compensation forthe unequal temperature coefficients of expansion between said steel and aluminum alloy members whereby said heating panel is not adversely affected by high operating temperatures and temperature gradients.

2. In a radiant electric heating panel, a generally rectangular frame having a pair of open sides, a plurality of coplanar heating elements adjacent one of said open sides adapted to propagate heat vertically with respect thereto, a reflector for said panel substantially closing the remaining open side of said frame comprising a rectangular reflecting surface substantially coextensive with said frame and having a central longitudinal peak therein extending upward toward said heating elements, and a pair of longitudinal troughs integral with the longitudinal extremities of said reflecting surface parallel to said peak and extending below and exteriorly of said frame, whereby foreign matter falling upon said reflecting surface between said heating elements will tend to flow from the peak of said reflecting surface into said troughs and thereafter be readily removable from said panel.

3. In a radiant heating panel, a generally rectangular frame having a pair of open sides, a plurality of coplanar heating elements adjacent one of said open sides adapted to propagate heat vertically with respect thereto, a reflector for said panel substantially closing the remaining open side of said frame comprising a peaked downward sloping reflecting surface coextensive with said frame and Open at the lower extremities thereof, whereby the radiant heat from said heating elements will be reflected and foreign matter falling on said reflecting surface between said heating elements will tend to flow from said reflector and out of said panel by the action of gravity.

4. In a radiant electric heating panel, a generally rectangular frame having a pair of open sides, a plurality of coplanar heating elements adjacent one of said open sides, adapted to propagate heat vertically with respect thereto, a reflector for said panel substantially closing the remaining open side of said frame comprising a rectangular refleeting surface substantially coextensive with said frame and having a central longitudinal peak therein extending upward toward said heating elements, said reflector comprising an aluminum alloy, a steel reinforcing channel having a V-shaped section opposed to and coextensive with said peak impositively secured to said reflector beneath said peak by means of a plurality of slidable bolt and slot connections, whereby the reflector is made light in weight and rigid in construction and the variance in the temperature coeflicients of expansion between steel and aluminum is automatically compensated by said slid able bolt and slot connections.

5. In a radiant heating panel, a generally rectangular frame having at least one open side, a plurality of coplanar heating elements adjacent said open side adapted to propagate heat vertically with respect to said open side, said heating elements comprising a plurality of parallel rods extending longitudinally of said frame, support means for said heating elements comprising, elongated vertical Web members extending transversely of said frame having open ended slots cut in the upper edges thereof for receiving said rods, said webs having the lower edges thereof turned in the shape of a return bend, and U-shaped brackets for slidably and freely receiving said lower edges of said webs at the ends thereof integrally mounted interiorly of said frame whereby buckling of said webs caused by expansion and contraction of said frame is prevented.

6. A radiant electric heating panel comprising a substantially rectangular frame including an aluminum alloy header box at one end thereof and an aluminum alloy end plate at the other interconnected at respective ends thereof by a pair of longitudinal aluminum alloy channel members integral with said header box and slidably interconnected with said end plate; said frame having a pair of open sides; an aluminum'alloy reflector closing one of the open sides of said frame integrally connected with said header box and said end plate and having a steel reinforcing member slidably interconnected therewith extending longitudinally thereof from a point immediately adjacent said header box to a point immediately adjacent said end plate, a plurality of U-shaped heating elements extending at the open ends thereof from said header box parallel to said channel members to the U-bends therein adjacent the said end plate; a plurality of parallel lateral supporting means for said heating elements extending across said frame member from one channel to the other, each of said supporting means comprising means integrally and oppositely disposed on each of said channel members, and elongated steel sections extending between said means and being freely retained therein; whereby the combination of said steel reinforcing and heating element supporting means with said aluminum alloy frame and reflector provide a light weight unit with high rigidity to resist buckling and twisting and said slidable connections between the steel members and the aluminum alloy members provide automatic compensation for the unequal temperature coefficients of expansion between said steel and aluminum alloy members whereby said heating panel is not adversely affected by high operating temperatures and temperature gradients.

7. In a radiant electric heating panel, a generally rectangular frame having a pair of open sides, a plurality of coplanar heating elements adjacent one of said open sides adapted to propagate heat vertically with respect thereto, a reflector for said panel substantially closing the remaining open side of said frame comprising a rectangular reflecting surface substantially coextensive with said frame and having a raised portion therein extending upward toward said heating elements, and a pair of longitudinal troughs integral with the longitudinal extremities of said reflecting surface positioned below said raised portion and extending below and exteriorly of said frame, whereby foreign matter falling upon said reflecting surface between said heating elements will tend to flow from the raised portion of said reflecting surface into said troughs and thereafter be readily removable from said panel.

8. In a radiant electric heating panel, a generally rectangular frame having a pair of open sides, a plurality of coplanar heating elements adjacent one of said open sides adapted to propagate heat vertically with respect thereto, a reflector for said panel substantially closing the remaining open side of said frame comprising a rectangular refleeting surface substantially coextensive with said frame and having a raised portion therein extending upward toward said heating elements, said reflector comprising an aluminum alloy, a steel reinforcing channel having a cross-section opposed to and coextensive with said raised portion slidably secured to said reflector beneath said raised portion by means of a plurality of slidable bolt and slot connections, whereby the reflector is made light in Weight and rigid in construction and the variance in the temperature COCffiClCIIlIS of expansion between steel and aluminum is automatically compensated by said slidable bolt and slot connections.

9. In a radiant heating panel, a generally rectangular frame having at least one open side, a plurality of coplanar heating elements adjacent said open side adapted to propagate heat vertically with respect to said open side, said heating elements comprising a plurality of parallel rods extending longitudinally of said frame, support means for said heating elements comprising, elongated vertical web members extending transversely of said frame 7 having open ended slots cut in the upper edges thereof I References Cited in the file of this patent for receiving said rods, said webs having the lower edges }UNITED STATES PATENTS thereof turned in the shape of a return bend, and means v for slidably and freely receiving said lower edges of said 1'535555 Thornton 28,1925 webs at the ends thereof integral with said frame whereby 5 gg g fi? 25 k '1 db an '0 a d ont action f I buc ling of said webs cause yexp S! n n c r 2,756,319 Hatch y 24 1956 of said frame is prevented. 

